Note 4 - Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

	As of December 31, 201 7
	Level 1		Level 2		Level 3		Tota l
Assets :
Cash and cash equivalent s	$	12,689	$	—	$	—	$	12,689

	As of December 31, 201 6
	Level 1		Level 2		Level 3		Tota l
Assets :
Cash and cash equivalent s	$	21,352	$	—	$	—	$	21,352